Thermal-recovery optimization of the SG-III prototype

Thermal recovery of the main amplifier of the SC-ill prototype is numerical ly simulated. The calculations indicate that, with a shot period of 4 h, we can achieve an acceptable laser slab average temperature and thermal gradi ent across the slab aperture through optimized active cooling for both the flashlamp cassettes and the slab cavities. After 4 h of thermal recovery, t he average temperature and the largest temperature drop across the aperture of the laser slab will be less than 0.13 degreesC above ambient and 0.11 d egreesC respectively. The active cooling for all the flashlamp cassettes wi ll need a total cleaned-air flow rate of 80 m(3)/min (10 ft(3)/min per lamp ) and a total nitrogen flow rate of 16 m(3)/min for all the slab cavities. Additionally, the temperature of the cooling gas in the flashlamp cassette must be reduced to -1.0 degreesC (relative to ambient temperature) during t he first 2.5 h of the thermal recovery cycle. (C) 2001 Society of Photo-Opt ical instrumentation Engineers.